Combine 1cup of whole wheat flour, water, sugar and yeast in a mixing bowl. Let the mixture rest for a few minutes until bubbles start to form. Stir in the remaining ½cup of whole wheat flour, salt and the oil.
Next stir in 1 cup of all purpose flour and mix it into the dough. Knead the dough on a clean work surface adding a bit more flour if needed to prevent sticking. Add the final ½cup of flour as needed to create a soft, smooth dough.
Transfer the dough into a lightly greased bowl, cover and let the dough rise until doubled in size, about 1½hours.
Gently deflate the dough and shape it into a 8" log. Place the log in a lightly greased 8½"x4½" loaf pan. Cover the loaf loosely with a greased plastic wrap and let it rise for another 30 minutes.
Preheat the oven to 375°F. Uncover the bread and bake for about 30 minutes or until the crust is golden brown and a digital thermometer inserted into the center reads 190°F.
Remove the bread from the oven and transfer to a wire rack to cool completely. Store at room temperature for 3~4 days or freeze for longer storage.